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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2011 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: CriteriaCallback.html 820 2014-01-22 16:41:52Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.dellroad.stuff.dao;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import javax.persistence.EntityManager;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import javax.persistence.TypedQuery;<a name="line.11"></a>
<span class="sourceLineNo">012</span>import javax.persistence.criteria.CriteriaBuilder;<a name="line.12"></a>
<span class="sourceLineNo">013</span>import javax.persistence.criteria.CriteriaQuery;<a name="line.13"></a>
<span class="sourceLineNo">014</span><a name="line.14"></a>
<span class="sourceLineNo">015</span>/**<a name="line.15"></a>
<span class="sourceLineNo">016</span> * Specialization of {@link QueryCallback} for {@link CriteriaQuery} queries.<a name="line.16"></a>
<span class="sourceLineNo">017</span> *<a name="line.17"></a>
<span class="sourceLineNo">018</span> * @param &lt;T&gt; query result type, i.e., what the {@link CriteriaQuery} returns zero or more of<a name="line.18"></a>
<span class="sourceLineNo">019</span> * @param &lt;R&gt; query Java return type, usually either {@code R} or {@code List&lt;R&gt;}<a name="line.19"></a>
<span class="sourceLineNo">020</span> */<a name="line.20"></a>
<span class="sourceLineNo">021</span>public abstract class CriteriaCallback&lt;T, R&gt; extends TypedQueryCallback&lt;T, R&gt; {<a name="line.21"></a>
<span class="sourceLineNo">022</span><a name="line.22"></a>
<span class="sourceLineNo">023</span>    protected final Class&lt;T&gt; type;<a name="line.23"></a>
<span class="sourceLineNo">024</span><a name="line.24"></a>
<span class="sourceLineNo">025</span>    protected CriteriaCallback(Class&lt;T&gt; type) {<a name="line.25"></a>
<span class="sourceLineNo">026</span>        if (type == null)<a name="line.26"></a>
<span class="sourceLineNo">027</span>            throw new IllegalArgumentException("null type");<a name="line.27"></a>
<span class="sourceLineNo">028</span>        this.type = type;<a name="line.28"></a>
<span class="sourceLineNo">029</span>    }<a name="line.29"></a>
<span class="sourceLineNo">030</span><a name="line.30"></a>
<span class="sourceLineNo">031</span>    /**<a name="line.31"></a>
<span class="sourceLineNo">032</span>     * Build the query by delegating to {@link #configureQuery configureQuery()} for configuration.<a name="line.32"></a>
<span class="sourceLineNo">033</span>     */<a name="line.33"></a>
<span class="sourceLineNo">034</span>    @Override<a name="line.34"></a>
<span class="sourceLineNo">035</span>    protected TypedQuery&lt;T&gt; buildQuery(EntityManager entityManager) {<a name="line.35"></a>
<span class="sourceLineNo">036</span>        final CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();<a name="line.36"></a>
<span class="sourceLineNo">037</span>        final CriteriaQuery&lt;T&gt; criteriaQuery = criteriaBuilder.createQuery(this.type);<a name="line.37"></a>
<span class="sourceLineNo">038</span>        this.configureQuery(criteriaQuery, criteriaBuilder);<a name="line.38"></a>
<span class="sourceLineNo">039</span>        return entityManager.createQuery(criteriaQuery);<a name="line.39"></a>
<span class="sourceLineNo">040</span>    }<a name="line.40"></a>
<span class="sourceLineNo">041</span><a name="line.41"></a>
<span class="sourceLineNo">042</span>    /**<a name="line.42"></a>
<span class="sourceLineNo">043</span>     * Configure the {@link CriteriaQuery}.<a name="line.43"></a>
<span class="sourceLineNo">044</span>     */<a name="line.44"></a>
<span class="sourceLineNo">045</span>    protected abstract void configureQuery(CriteriaQuery&lt;T&gt; criteriaQuery, CriteriaBuilder criteriaBuilder);<a name="line.45"></a>
<span class="sourceLineNo">046</span>}<a name="line.46"></a>
<span class="sourceLineNo">047</span><a name="line.47"></a>




























































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